Preparation of low-dust stabilisers

ABSTRACT

A description is given of an extrusion process for the preparation of a low-dust stabiliser, using a subcooled melt as granulation liquid, as well as of novel amorphous modifications of different stabilisers, including 2,2′-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol), and of the β-crystalline modification of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole and of the preparation thereof. The novel process affords products which are easy to handle and which are flowable, and the novel modifications have advantages as regards their preparation, processing and their use as stabiliser.

[0001] The present invention relates to a process for the preparation oflow-dust stabilisers by extruding a subcooled melt, to the use of theproducts of this process for stabilising organic polymers, to novelamorphous modifications, e.g. of2,2′-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol),to a novel crystalline modification of2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, to aprocess for its preparation and processing as well as to compositionsstabilised therewith.

[0002] The development of stabiliser which are low-dust and thereforegenerally easier to handle has been pursued for some time; specificstabilisers have, inter alia, been mounted on inorganic substrates (e.g.U.S. Pat. No. 5,238,605).

[0003] GB-A-2267499 describes the preparation of a mixture oftetraalkylpiperidine type stabilisers of high and low molecular weightby mixing in a melted state.

[0004] U.S. Pat. No. 5,597,857 describes a process for the preparationof low-dust stabilisers by extruding a calcium stearate melt;JP-A-59-104348 and EP-A-565184 also propose extruding a melt.DE-A-19541242 proposes pastillising a mixture consisting of crystallineand melted plastic additives.

[0005] The use of a regular melt during extrusion is only possible to alimited degree owing to its low viscosity.

[0006] Amorphous modifications of individual stabilisers and their usefor stabilising organic polymers have already been described, interalia, in EP-A-278579, U.S. Pat. No. 4,683,326, EP-A-255743, U.S. Pat.No. 5,373,040, U.S. Pat. No. 5,489,636, JP-A-59-104348, U.S. Pat. No.5,574,166. They are usually prepared by rapidly cooling (chilling) themelt to prevent crystallisation. EP-A-278579 describes the preparationof a partially crystalline stabiliser mixture consisting of amorphoustetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneand a crystalline organic phosphite by subcooling the melt.

[0007] EP-A-514784 describes the extrusion oftetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneand the mixtures thereof with inorganic salts of fatty acid salts attemperatures in the melting range.

[0008] Surprisingly, it has now been found that the metastable statewhich is passed during the preparation of low molecular weight amorphousstabilisers, the subcooled melt, is excellently suitable for use asgranulation liquid or binder during the extrusion. It is remarkable thatthe formation of crystalline modifications of the low molecular weightstabilisers is unexpectedly highly inhibited, making it possible toprocess the plastic extrusion compositions to granules by conventionalmethods.

[0009] Accordingly, this invention relates to a process for thepreparation of a low-dust stabiliser, which comprises extruding asubcooled melt of a stabiliser having a molecular weight of 200 to 1500g/mol, or the plastic composition of the mixture consisting of thesubcooled melt of the stabiliser and of a crystalline stabiliser and/orother customary additives. The plastic composition therefore consists ofthe subcooled melt as homogeneous continuous phase and, whereappropriate, of further components dispersed therein (dispersephase(s)).

[0010] The processing to marketable, low-dust, flowable andstorage-stable forms with good meterability, e.g. for pelletisation,pastillation, melt granulation and compounding, is thus madesubstantially easier or possible at all. The moulding of the productcan, for example, also be carried out before or during the coolingprocess by dividing the subcooled melt or the mixture, for example bydripping in the liquid state or by dividing in the plastic state withsubsequent cooling. The process of this invention therefore alsoencompasses a process for granulating a stabiliser, which comprisesextruding and dividing a subcooled melt of the stabiliser or the plasticcompound consisting of the mixture of the subcooled melt of thestabiliser and of crystalline stabiliser and/or other customaryadditives. Solidification after extrusion gives a low-dust stabiliser,e.g. as granules.

[0011] This invention also relates to the granules obtainable by thenovel process as well as to the use of a subcooled melt for extruding astabiliser or stabiliser mixture, in particular for pelletisation, meltgranulation or compounding.

[0012] The subcooled melt is single-phase and accordingly has only onesingle glass transition temperature; it can, however, consist of one orseveral chemical compounds and it preferably consists of 1 to 3 maincomponents. Main components are to be understood as being thosecompounds, the proportion of which in the subcooled melt is 10% byweight or more, preferably 30% by weight or more. Also important is asubcooled melt which consists mainly, i.e. usually to 60% by weight ormore, preferably to 70% by weight or more, of 1 chemical compound(weight always being based on the total weight of the homogeneoussubcooled melt).

[0013] The amount oftetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methanein the subcooled melt is preferably less than 80% by weight, morepreferably from 0-60% by weight. A particularly important process ofthis invention is that, whereintetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methaneis not a main component of the subcooled melt.

[0014] The molecular weight of the chemical compounds forming thesubcooled melt (main components) is usually 300-1200 g/mol, preferably300-1000 g/mol, particularly preferably 500-1000 g/mol. These chemicalcompounds are normally one or several organic compounds, for examplehydrocarbons containing 6 to 100 carbon atoms and, where appropriate, 1to 30 hetero atoms, such as O, N, S, P, halogen. The melting point(m.p.) of the chemical compound, which forms a main component,preferably any component present to more than 5% by weight, is usually130° C. or higher, preferably 140° C. or higher, more preferably 170° C.or higher, and the glass transition temperature (T_(G)) is in the rangefrom 10-120° C., preferably from 20-100° C. The ratio of glasstransition temperature (T_(G)) to melting point (m.p.), each measured inKelvin (K), is preferably in the range from 0.6 to 0.9; more preferablyin the range from 0.65 to 0.85.

[0015] The compounds which form the subcooled melt are usually lightstabilisers or antioxidants, for example those cited in the list givenhereinbelow under the items 1, 2 and 4, provided they meet the statedcriteria regarding molecular weight, melting point and glass transitiontemperature. They preferably belong to the class consisting of UVabsorbers, sterically hindered amines (HALS), phenolic antioxidants,phosphites, phosphonites, lactones. In the novel process it is generallypossible to use those compounds which, by themselves or as mixtures, areobtainable also in single-phase amorphous form by chilling the melt.

[0016] The following compounds are preferably used in the novel process:

[0017] 2) bis(2-methyl-4-hydroxy-5-tert-butylphenyl)sulfide (CAS reg.No. 000096-69-5),

[0018] 3) (CAS reg. No. 069851-61-2),

[0019] 4)N,N′-bis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionyl)hexamethylenediamine(CAS reg. No. 023128-74-7),

[0020] 5)1,3,5-trimethyl-2,4,6-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)benzene(CAS reg. No. 001709-70-2),

[0021] 6)1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione(CAS reg. No. 027676-62-6),

[0022] 7) (CAS reg. No. 032687-78-8),

[0023] 8)1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)1,3,5-triazine-2,4,6-(1H,3H,5H)trione(CAS reg. No. 040601-76-1),

[0024] 9)di(1,2,2,6,6-pentamethylpiperidin-4-yl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate(CAS reg. No. 063843-89-0),

[0025] 10)2-(2′-hydroxy-3′,5′-bis(1,1-dimethylbenzyl)phenyl)benzotriazole (CASreg. No. 070321-86-7) of formula

[0026] 11) 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole (CASreg. No.003846-71-7);

[0027] 12) isomeric mixtures (CAS reg. No. 181314-48-7) consisting ofabout 85% by weight of5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)-benzofuranone andabout 15% by weight of5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone;

[0028] 13)pentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)(CAS reg. No. 006683-19-8);

[0029] 14) 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole(CAS reg. No. 3864-99-1)

[0030] 15) (CAS reg. No. 080410-33-9);

[0031] 16) tris(2,4-di-tert-butylphenyl)phosphite (CAS reg.No.031570-04-4);

[0032] 17) (CAS reg. No. 26741-53-7);

[0033] 18) CAS reg. No. 37042-77-6);

[0034] 19)2-[2′-hydroxy-3′-(α-α-dimethylbenzyl)-5′-(1,1,3,3-tetramethyl-butyl)phenyl]benzotriazoleor formula (CAS reg. No. 073936-91-1).

[0035] The following Table provides the molecular weight (Mw), meltingpoint (m.p.; DSC +4° C./min), melt enthalpy (ΔH), glass transitiontemperature (Tg; DSC +20° C./min) and preferred processing temperature(Tp) of these compounds: com- Tp (° C.) pound Mw (g/mol) m.p. (° C.) ΔH(J/g) Tg (° C.) about  1) 658 197 86 70-80  90-140  2) 358 161 113 25-3540-60  3) 594.8 177 93 55-65  70-100  4) 636.9 160 96.5 50-60  70-130 5) 775 179/243* 200/65*   90-100 105-125  6) 784 220 75 105-115 115-140 7) 553 200/229*  50/120* 65-75  75-100  8) 699 158 20.5 110-120 120-155 9) 685 148 80 40-50  55-145 10) 447.6 139 84 35-45  55-100 11) 323.4154 88.5 15-25 25-40 12) 350.5 132 90 20-30 40-80 13) 1177.6 105-125*50-72* 40-55 65-95 14) 357.9 157 80 20-30 30-40 15) 1465 203 46.5105-115 130-200 16) 646.9 186 71 35-45 50-70 17) 604 172 65 45-55 65-8018) 552 163 ca.120 50-60  70-150 19) 441.4 113 64-65  30-40  50-100

[0036] The subcooled melt is conveniently obtained by rapidly cooling aregular melt, the final temperature being below the melting point (m.p.)of the main component, preferably below the regular melting point (m.p.)of the component having the lowest melting point (usually called onlymelting point hereinafter). The final temperature is preferably in therange of the processing temperature stated further on. The coolingprocess can be carried out in a manner known per se, for example byintroducing a melt to the cooled extruder, melting the stabiliser in theextruder and then transporting the melt into a corresponding cooledzone, or by preparing the subcooled melt outside of the extruder. Themelt can result direct from the synthesis of a compound or from meltingone or several compounds. The subcooled melt can also be obtained byrapidly melting a solid amorphous compound to a temperature from theglass transition temperature to the melting point of the crystallinemodification, preferably in the range of the processing temperature.Depending on the cooling method or cooling speed, the melt can also beprocessed to an amorphous or partially amorphous product, for examplepellets, using a melt screw or extruder.

[0037] It has furthermore been found that the subcooled single-phasemelt can surprisingly also contain a smaller proportion of compounds,for example up to 40% by weight, in particular up to 30 or 20% byweight, in dissolved form, the glass transition temperature (T_(G)) ofwhich is below 10° C., meaning that they cannot be obtained in amorphousform by chilling processes using customary cooling temperatures up toabout 0° C.; the precondition being that the glass transitiontemperature of the resulting phase is above 10° C., in particular above20° C. These compounds usually also belong to the group of the lightstabilisers or antioxidants as indicated above for the compounds formingthe subcooled melt.

[0038] The subcooled melt and components which may be dispersed thereinform the extrudable plastic composition. The subcooled melt component inthe novel extrusion is preferably from 5 to 100% by weight, morepreferably from 20 to 100% by weight, most preferably from 50 to 100% byweight, of the plastic composition. Other dispersed components, ifpresent, are preferably crystalline at the processing temperature.Dispersed further components are usually conventional additives, forexample the classes and products cited hereinbelow as possibleco-additives. It is preferred to use, in particular, phenolicantioxidants, organic phosphites or phosphonites as well as stericallyhindered amines.

[0039] Extrusion will be understood in this connection as being anyprocess warranting a transport of the plastic composition, often via ascrew, with suitable tempering. The plastic composition is usuallyadditionally mixed and/or moulded after passage through a tempered zone,for example to granules, pellets or strands.

[0040] The plastic additives (stabilisers) are advantageously processedin a single- or twin-screw extruder. Such extruders are known in theplastics processing industry and are marketed, for example, by Buss(CH), Brabender (DE), Werner and Pfleiderer (DE) or Bühler (CH).

[0041] After or also while the still-soft extruded product is cut andafter passage through a die or perforated plate, the granule particlesare often cooled. Cooling can be carried out in the form of wet coolingwith water (for example in water, via a water film, water ring etc.) or,preferably, with air (for example air film, air vortex etc.), or alsocombined. Cooling with water requires subsequent dehydration and drying(preferably in a vortex drier or fluidised-bed drier). The technicalimplementations of these cooling methods are known. Granulation ispreferably carried out while the material is still in the plastic state,prior to the actual cooling step, in contrast to the extrusiongranulation and grinding process usual in the state of the art.

[0042] The processing temperature of the plastic composition ispreferably about in the middle between the regular melting point (m.p.)and the glass transition temperature (T_(G)) of the homogeneous phase.The processing temperature is preferably in the range from T_(MIN) toT_(MAX), where with (m.p.)−(T_(G))=Δ:

T _(MIN) =T _(G)+0.2 Δ

T _(MAX) =T _(G)+0.6 Δ;

[0043] particularly preferably:

T _(MIN) =T _(G)+0.3 Δ

T _(MAX) =T _(G)+0.5 Δ..

[0044] In other of its aspects, this invention relates to granules whichare obtainable by the novel process as well as to the use of a subcooledmelt of a stabiliser for extrusion, in particular for pelletisation,melt granulation or compounding.

[0045] Depending on the implementation and cooling conditions, the novelprocess affords a crystalline, partially crystalline or completelyamorphous product.

[0046] Accordingly, this invention also relates to a single-phaseamorphous stabiliser comprising 2 or more compounds having have amolecular weight in the range from 300-1000 g/mol.

[0047] Novel amorphous modifications

[0048] This invention also relates to novel amorphous forms ofstabiliser, known so far only in their crystalline modification, namelythe compounds

[0049] 1)2,2′-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol)(CAS reg. No. 10359745-1) of formula

[0050] 2) bis(2-methyl-4-hydroxy-5-tert-butylphenyl)sulfide (CAS reg.No. 000096-69-5),

[0051] 3) (CAS reg. No. 069851-61-2),

[0052] 4)N,N′-bis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionyl)hexamethylenediamine(CAS reg. No. 023128-74-7),

[0053] 5)1,3,5-trimethyl-2,4,6-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)benzene(CAS reg. No. 001709-70-2)

[0054] 6)1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione(CAS reg. No. 027676-62-6)

[0055] 7) (CAS reg. No. 032687-78-8)

[0056] 8)1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)1,3,5-triazine-2,4,6-(1H,3H,5H)trione(CAS reg. No. 040601-76-1)

[0057] 9)di(1,2,2,6,6-pentamethylpiperidin-4-yl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate(CAS reg. No. 063843-89-0),

[0058] 10)2-(2′-hydroxy-3′,5′-bis(1,1-dimethylbenzyl)phenyl)benzotriazole (CASreg. No. 070321-86-7) of formula

[0059] 11) 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole (CASreg. No.003846-71-7);

[0060] 12) isomeric mixture of5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)benzofuranone and5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone;

[0061] 14) 2-(2-hydrozy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole,synonymous with 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl, phenol(CAS reg. No. 3864-99-1), of formula

[0062] 18) (CA-reg. No. 3704277-6)

[0063] Compound 12, an isomeric mixture, has the CAS reg. No.181314-48-7and consists of about 85% by weight5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)-benzofuranone andabout 15% by weight5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone.

[0064] These compounds are at the same time particularly preferredcompounds for use in the extrusion process described at the outset.

[0065] The cited compounds are effective for stabilising organicmaterial against the harmful action of light, heat and oxygen. Compound(1) and its use has been described, inter alia, in U.S. Pat. No.4,812,498, U.S. Pat. No. 4,948,666, U.S. Pat. No. 4,681,905, and itspreparation in U.S. Pat. No. 5,229,521 and U.S. Pat. No. 4,812,498;compound (14) is particularly effective as UV absorber and itspreparation is described, inter alia, in U.S. Pat. No. 4,001,266, U.S.Pat. No. 4,041,044, U.S. Pat. No. 4,219,480, U.S. Pat. No. 4,230,867 andU.S. Pat. No. 4,999,433; the known a-modification of compound (14) has,in pure form, a melting point of about 156° C. and is commerciallyavailable under the trade name Tinuvin® 327.

[0066] The novel amorphous forms of compound 1-12, 14, and 18 give aline-free X-ray diffraction diagram, e.g. with Cu-kα-radiation. They arealso characterised by their glass transition temperature (Tg) which, forexample in compound 14, is in the range from 20-30° C., in particularfrom 20-25° C.

[0067] The preparation of the amorphous form of compounds 1-12, 14 andalso 18 is conveniently carried out by the novel process or, inparticular, by rapidly cooling (chilling) the melt, preferably startingfrom a temperature of a little above the melting point or higher,typically 1-30° C. above the melting point, to a temperature below theglass transition temperature (Tg), for example 20-50° C. below Tg.

[0068] This can be done in known manner, for example by application to acooled surface (e.g. a cooling conveyer), introduction into a coolednonreactive liquid or by cooling in a stream of gas, for example withair or nitrogen. The temperature of the solid or liquid cooling mediumis preferably below 100° C., in particular below 50° C., for example inthe range from 0-50° C., preferably in the range from 5-20° C.; thetemperature of the stream of gas used for cooling is preferably 20° C.or lower, for example in the range from 0-20° C., preferably from 0-10°C.

[0069] The preparation of the amorphous form of compound 14 isconveniently carried out by rapidly cooling (chilling) a melt of thecompound, preferably starting from a temperature of 159° C. or more to atemperature of 20° C. or lower.

[0070] This can be done in known manner, for example by application to acooled surface, introduction into a cooled nonreactive liquid or bycooling in a stream of gas, for example with air or nitrogen. Thetemperature of the cooling medium is preferably below 20° C., inparticular below 10° C., for example in the range from −10 to +15° C.,preferably from −5 to +5° C.

[0071] The amorphous solid so obtained can be comminuted by knownmethods, for example by grinding, to any desired particle size, theproduct temperature conveniently being kept below the glass transitiontemperature.

[0072] The novel amorphous modifications are distinguished over thecrystalline modifications by a number of advantages, inter alia, inpreparation, further processing and use. Rapidly cooling the melt tobelow the glass transition temperature, for example, results in the heatof crystallisation not being released (in the case of cmpd. (1) about85-88 J/g), so that less energy needs to be eliminated by cooling andthe cooling time of the oxidation-sensitive products can be reduced. Theincorporation and distribution in the material to be stabilised isfurthermore facilitated by the lack of heat of fusion. The novelmodifications are dissolved more easily and homogeneously in, on the onehand, organic solvents, such as lubrication oils, lubricants, urethanes,prepolymers and others and, on the other hand, in the organic materialto be stabilised, for example the organic polymer. Thus it is possibleto achieve a more uniform distribution in the substrate, to preventinhomogeneity as well as to obtain good processibility and excellenteffectiveness.

[0073] In addition, the plastic metastable state of the subcooled meltsmakes processing in the extruder possible, where either the pureamorphous form can be used or a mixture consisting of the novelamorphous modification and of the customary crystalline form and/orother customary additives.

[0074] This invention therefore also relates to a mixture consisting ofa subcooled melt or of an amorphous solid of one or several of compounds1-12, 14, and 18, of a crystalline compound and/or of a customarystabiliser, the proportion of the novel amorphous modificationpreferably being from 5 to 100% by weight, in particular from 20 to 100%by weight, of the mixture and wherein, in particular, the customarystabiliser can be either solid or also amorphous.

[0075] Particularly important are in this connection the amorphousmixtures which usually have the same advantageous application propertiesas the amorphous single compounds. Many low molecular weight compounds,such as those cited above, are soluble in one another in the melt andare capable of forming eutectic mixtures. In mixtures, the componenthaving the lowest melting point can serve as solvent for one or severalother components. Thus it is possible to obtain multicomponentsingle-phase amorphous mixtures which are distinguished by having onlyone single glass transition temperature Tg.

[0076] Owing to the interaction of the individual compounds, the mixturephysically has a novel amorphous structure, the Tg value of which can bederived from the Tg values of the individual amorphous modifications andtheir concentration. Accordingly, it is possible to selectively preparesingle-phase microhomogeneous mixtures by mixing these compounds withone another or by admixing other low molecular weight additives, such asthe compounds No. 13, 15, 16, 17 which, as is known, also have anamorphous modification. It is even possible to use some additives whichare only known in crystalline form, the Tg of which is far below 15° C.(e.g. compound bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate) in asmall amount. The glass transition temperature can here be adjustedpreferably to between 40 and 100° C. by skillful combination of thecompounds to warrant on the one hand an amorphous stabiliser which meltseasily and at low temperature (energetically favourable, advantageousfor certain applications) and, on the other hand, good storagestability.

[0077] Novel crystalline modification of compound No. 14

[0078] It has furthermore been found that a novel crystal modification(β-form; high-temperature modification) can be obtained by equilibrating2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compoundNo. 14) in a specific temperature range. This crystal modification isdistinguished over the conventional α-crystalline form by enhancedperformance properties, such as higher bulk density and compacted bulkdensity, flowability, improved dispersibility in the substrate and lessevolution of dust when handled and this modification also constitutes anobject of this invention.

[0079] The physical properties of the novel β-modifications of compound14 have a number of differences as compared to the α-modification, someof which have been found to be as follows: α-modification β-modificationmelting point 156° C. 158° C. contact angle of benzyl alcohol  24.5° 19.5° loose bulk density  0.39 kg/l  0.49 kg/l compacted bulk density 0.72 kg/l  0.79 kg/l compressibility  46%  38% angle of repose  54° 50° flow factor (acc. to Jenike)  1.6  2.6

[0080] The following Table provides the interplanar spacings determinedby X-ray diffraction (Cu-kα-radiation; measurement of the powderdiagrams in transmission geometry using a Guinier camera) for the knownα-form as well as for the novel β-crystalline form (d, given in Å=10⁻¹⁰m) and reflection intensities (visually determined): α-modificationβ-modification d [Å] intensity d [Å] intensity 16.0 medium 16.1 weak 9.8strong 9.4 strong 8.6 very weak 8.0 very strong 8.0 very strong 7.2 weak6.4 weak 5.88 weak 5.99 medium 5.61 medium 5.61 weak 5.42 weak 5.43 weak5.37 weak 5.07 very weak 5.22 very weak 4.83 strong 4.84 strong 4.58strong 4.69 strong 4.55 strong 4.49 medium 4.30 weak 4.18 very weak 4.04very weak 4.15 very weak 3.99 strong 3.94 very strong 3.87 very strong3.79 medium 3.71 very weak 3.63 very weak 3.63 very weak 3.62 very weak3.20 very weak 3.43 very weak 3.13 medium 3.34 very weak 3.10 very weak3.23 medium 3.04 weak 3.20 very weak 2.94 medium 3.09 very weak 2.90very weak 3.03 medium 2.92 weak

[0081] Characteristic of the β-form are, for example, the reflexescorresponding to the interplanar spacings (d) at d=9.4·10⁻¹⁰ m; atd=4.69·10⁻¹⁰ m; d=3.94·10⁻¹⁰ m and d=3.79·10⁻¹⁰ m (high or mediumintensity).

[0082] The inventive modification of compound 14 can be obtained byequilibrating the compound at a temperature of above 70° C., preferablyabove 95° C., more preferably above 106° C., and then cooling itrapidly, preferably to 15-20° C. or lower. Suitable for equilibrationare, for example, tempering as well as dissolving and/or meltingprocesses with mixing, for example during the extrusion in the novelprocess. Crystallisation prior to the cooling process gives theβ-crystalline form, the amorphous form being obtained otherwise.

[0083] The preparation of the β-crystalline form is conveniently carriedout by crystallising compound 14 above 70° C., typically above 95-106°C., preferably above 106° C., or by tempering the α-crystalline form inthe temperature range from 70° C., preferably from 95° C., mostpreferably from 106° C., and at a melting point of the α-crystallineform; i.e. typically in the range from 106° C. to 155° C., preferablyfrom 110C. to 150° C., with subsequent rapid cooling of theβ-crystalline form obtained typically to 50° C. or lower, preferably to15-30° C. or room temperature (20-25° C.) or lower.

[0084] Crystallisation can be carried out by the customary methods ofthe art, for example by crystallisation from a solution or subcooledmelt of compound which is kept below the melting point, or by cooling amelt.

[0085] The cooling process from a temperatur of above 70° C., such asabove 95-106° C. or above 156° C., to 50° C. or room temperature canproceed continuously or discontinuously, the cooling rate being slowedor stopped in the range from 95 to 156° C., preferably from 106-150° C.The cooling process can usefully also be combined with the moulding ofthe product, e.g. granulation or pastillation. Typical examples ofconcrete processes are fluid bed granulation or prilling.

[0086] For tempering, the compound is heated either direct or withaddition of a suitable solvent, e.g. xylene, toluene or a mixture ofxylene and butanol with a sufficiently high boiling point, convenientlyfor about 20 minutes to 24 hours to a temperature in the cited range.Cooling is then carried out as indicated above.

[0087] Suitable solvents are, for example, those having a boiling pointwhich is markedly higher than 95° C., in particular higher than 106° C.,at normal pressure, preferably alcohols or hydrocarbons, such astoluene, xylene or mesitylene or their mixtures. The use of solventshaving lower boiling points is also possible, in which case the pressureis usefully increased such that the solvent remains liquid in the citedtemperature range. Such solvents can subsequently be removed more easilythan the high-boiling solvents mentioned at the outset.

[0088] When using a solvent, compound 14 can also be dissolvedcompletely or partially, and the crystallisation of the dissolvedcomponents can then be achieved, inter alia, by gentle cooling to thelower range of the cited temperature range, for example to 70-100° C.,95-110° C. or 106-120° C., and/or by removing the solvent bydistillation.

[0089] The β-crystalline product can, if required, be brought into anyother desired form of presentation and particle size by known methods,such as grinding, compressing, extruding or granulating.

[0090] The use of mixtures of the novel modifications with one anotherand with the customary α-crystalline modification has also advantages ofthe cited kind over the use of the pure α-crystalline modification. Thenovel mixture consisting of different modifications of compound 14preferably contains at least 40% by weight, preferably at least 60% byweight, more preferably at least 80% by weight, of β-crystalline and/oramorphous form and not more than 50% by weight, preferably not more than20% by weight, more preferably not more than 10% by weight, of foreigncomponents (each based on the total weight of the mixture).

[0091] Another advantage of the novel B-modification of compound 14consists in the easier and more homogeneous solubility in, on the onehand, organic solvents, such as lubrication oils, lubricants, urethanes,prepolymers and others and, on the other hand, in the organic materialto be stabilised, for example the organic polymer, such that a moreuniform distribution is achieved therein, inhomogeneity is prevented andexcellent effectiveness is warranted.

[0092] The novel modifications of compound 14 are particularly suitablefor stabilising organic materials, for example in particular the organicpolymers cited hereinbelow, against damage by light, oxygen or heat. Thenovel modifications are very particularly suitable as light stabilisers(UV absorbers).

[0093] Colour-stabilisation of compound No.13

[0094] Amorphouspentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)(CAS reg. No.006683-19-8; compound No.13), which is usually obtained asa colourless powder during synthesis, quickly darkens during storage,the product taking on a greenish to yellow hue (greening). Depending onthe storage conditions, in particular on exposure to light and oxygen,this unwanted effect occurs usually after about 4-12 weeks.

[0095] The use of mixtures comprising this compound in the novelextrusion process surprisingly shows that in the case of certainadditives the colour stability of the amorphous compound 13 is markedlyimproved and the greening effect is prevented or at least slowed downvery much. It is important in this connection that a microhomogeneousamorphous mixture is obtained.

[0096] In another of its aspects, this invention therefore also relatesto a process for stabilising the colour of amorphouspentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate),which comprises admixinga stabiliser of the class consisting of theorganic phosphites, phosphonites and/or benzofuran-2-ones to a melt ofpentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)and rapidly cooling the mixture so obtained.

[0097] The use of a stabiliser of the class consisting of the organicphosphites, phosphonites and/or benzofuran-2-ones for stabilising thecolour of amorphouspentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)is another object of this invention.

[0098] The compound No. 13 colour-stabilised in this manner forms amicrohomogeneous phase together with the stabiliser. The stabilisercomponent (organic phosphite, phosphonite and/or benzofuran-2-one) inthis phase is preferably at least 1% by weight, typically 1-95% byweight, in particular 5-90% by weight, more preferably 5 to 55% byweight.

[0099] The cooling process which gives the partially amorphous or,preferably, single-phase amorphous colour-stabilised compound No. 13 canbe carried out in the manner described above for the preparation of thenovel amorphous modifications.

[0100] In this connection, phosphites or organic phosphites will beunderstood as meaning the compounds of formula P(OR)3, wherein theradicals R are hydrocarbon radicals which may contain hetero atoms, andwhere a maximum of two of the three radicals R may additionally behydrogen atoms. Hetero atoms are all atoms with the exception of carbonand hydrogen, in particular the N, O, F, Si, P, S, Cl, Br, Sn and Iatoms.

[0101] Phosphonites are esters of the phosphonous acid of formulaP(OR)₂R, wherein R has the meanings given above or may be halogen.

[0102] Phosphites or phosphinites preferably used in the inventiveprocess are those, which correspond to one of formulae (1) to (7),

[0103] wherein the indices are integers, and

[0104] n′ is 2, 3 or 4; p is 1 or 2; q is 2 or 3; r is 4 to 12; y is 1,2 or 3; and z is 1 to 6;

[0105] A′, if n′ or q is 2, is alkylene of 2 to 18 carbon atoms;alkylene of 2 to 12 carbon atoms which is interrupted by —S—, —O— or—NR′₄—; a radical of one of formula

[0106] or phenylene;

[0107] A′, if n′ or q is 3, is a radical of formula —C_(r)H_(2r-1)—;

[0108] A′, if n′ is 4, is the radical of formula C(CH₂)₄;

[0109] A″ has the meaning of A′, if n′ is 2;

[0110] B′ is a radical of formula —CH₂—; —CHR′₄—; —CR′₁R′₄—; —S— or adirect bond; or C₅-C₇cycloalkylidene; or cyclohexylidene which issubstituted by 1 to 4 C₁-C₄alkyl radicals in position 3, 4 and/or 5;

[0111] D′, if p is 1, is methyl and, if p is 2, is —CH₂OCH₂—;

[0112] E′, if y is 1, is alkyl containing 1 to 18 carbon atoms, aradical of formula —OR′, or halogen;

[0113] E′, if y is 2, is a radical of formula —O—A″—O—;

[0114] E′, if y is 3, is a radical of formula R′₄—C(CH₂O)₃—;

[0115] Q′ is the radical of an at least z-valent alcohol or phenol,which radical is bound via the alcoholic or phenolic O-atom(s) to theP-atom(s);

[0116] R′₁, R′₂ and R′₃ are each independently of one another alkylcontaining 1 to 30 carbon atoms; alkyl containing 1 to 18 carbon atoms,which is substituted by halogen, —COOR₄′, —CN or —CONR₄′R₄′; alkylcontaining 2 to 18 carbon atoms, which is interrupted by —S—, —O— or—NR′₄—; phenyl-C₁-C₄alkyl; cycloalkyl containing 5 to 12 carbon atoms;phenyl or naphthyl; phenyl or naphthyl, each of which is substituted byhalogen, 1 to 3 alkyl radicals or alkoxy radicals containing a total of1 to 18 carbon atoms or by phenyl-C₁-C₄alkyl; or a radical of formula

[0117] wherein m is an integer from the range of 3 to 6;

[0118] R′₄, or the radicals R₄′, are each independently of one anotherhydrogen; alkyl containing 1 to 18 carbon atoms; cycloalkyl containing 5to 12 carbon atoms; or phenylalkyl containing 1 to 4 carbon atoms in thealkyl moiety;

[0119] R′₅ and R′₆ are each independently of the other hydrogen; alkylcontaining 1 to 8 carbon atoms, or cycloalkyl containing 5 or 6 carbonatoms;

[0120] R′₇ and R′₈, where q=2, are each independently of the otherC₁-C₄alkyl or are together a 2,3-dehydropentamethylene radical; and

[0121] R′₇ and R′₈, where q=3, are methyl;

[0122] the substituents R′₁₄ are each independently of one anotherhydrogen; alkyl containing 1 to 9 carbon atoms or cyclohexyl;

[0123] the substituents R′₁₅ are each independently of one anotherhydrogen or methyl; and

[0124] R′₁₆ is hydrogen or C₁-C₄alkyl, and in the case where severalradicals R′₁₆ are present, the radicals R′₁₆ are identical or different;

[0125] X′ and Y′ are each a direct bond or —O—; and

[0126] Z′ is a direct bond; —CH₂—; —C(R′₁₆)₂— or —S—.

[0127] A particularly preferred process is that, wherein the phosphiteor phosphonite is one of formula (1), (2), (5) or (6), wherein

[0128] n′ is the number 2, and y is the number 1 or 2;

[0129] A′ is alkylene containing 2 to 18 carbon atoms; p-phenylene orp-biphenylene;

[0130] E′, where y=1, is C₁-C₁₈alkyl, —OR₁ or fluoro; and where y=2, isp-biphenylene;

[0131] R′₁, R′₂ and R′₃ are each independently of one another alkylcontaining 1 to 18 carbon atoms; phenyl-C₁-C₄alkyl; cyclohexyl; phenyl;phenyl which is substituted by 1 to 3 alkyl radicals containing a totalof 1 to 18 carbon atoms;

[0132] the substituents R′₁₄ are each independently of one anotherhydrogen or alkyl containing 1 to 9 carbon atoms;

[0133] R′₁₅ is hydrogen or methyl;

[0134] X′ is a direct bond;

[0135] Y′ is —O—; and

[0136] Z′ is a direct bond or —CH(R′₁₆)—.

[0137] Of particular technical interest are those phosphites orphosphonites which are listed hereinafter in the list of possiblecostabilisers under item 4.

[0138] In the novel process those benzofuran-2-ones are preferably used,which correspond to formula (8)

[0139] wherein, if n is 1,

[0140] R₁ is naphthyl, phenanthryl, anthryl,5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl,benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, dibenzofuryl,chromenyl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl,pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl,indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl,naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl,carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl,phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl,furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of whichis unsubstituted or substituted by C₁-C₄alkyl, C₁-C₄alkoxy,C₁-C₄alkylthio, hydroxy, halogen, amino, C₁-C₄alkylamino, phenylamino ordi(C₁-C₄alkyl)amino, or R₁ is a radical of formula 9

[0141] and

[0142] if n is 2,

[0143] R₁ is unsubstituted or C₁-C₄alkyl- or hydroxy-substitutedphenylene or naphthylene; or —R₁₂—X—R₁₃—,

[0144] R₂, R₃, R₄ and R₅ are each independently of one another hydrogen,chloro, hydroxy, C₁-C₂₅-alkyl, C₇-C₉phenylalkyl, unsubstituted orC₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substitutedC₅-C₈cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino,di(C₁-C₄-alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino,C₃-C₂₅alkenoyloxy; C₃-C₂₅alkanoyloxy which is interrupted by oxygen,sulfur or

[0145] C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substitutedbenzoyloxy; or R₂ and R₃, or R₃ and R₄, or R₄ and R₅, together with thelinking carbon atoms, are a benzene ring, R₄ is additionally—(CH₂)_(p)—COR₁₅ or —(CH₂)_(q)OH or, if R₃, R₅ and R₆ are hydrogen, R₄is additionally a radical of formula 10

[0146] wherein R₁ is as defined above for n=1,

[0147] R₆ is hydrogen or a radical of formula 11

[0148] wherein R₄ is not a radical of formula 10 and R₁ is as definedabove for n=1,

[0149] R₇, R₈, R₉, R₁₀ and R₁₁ are each independently of one anotherhydrogen, halogen, hydroxy, C₁-C₂₅alkyl; C₂-C₂₅alkyl which isinterrupted by oxygen, sulfur or

[0150] C₁-C₂₅alkoxy; C₂-C₂₅alkoxy which is interrupted by oxygen, sulfuror

[0151] C₁-C₂₅alkylthio, C₃-C₂₅-alkenyl, C₃-C₂₅alkenyloxy, C₃-C₂₅alkynyl,C₃-C₂₅alkynyloxy, C7-C₉phenylalkyl, C₇-C₉phenylalkoxy, unsubstituted orC₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substitutedphenoxy; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl;unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkoxy;C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyl; C₃-C₂₅alkanoylwhich is interrupted by oxygen, sulfur or

[0152] C₁-C₂₅alkanoyloxy; C₃-C₂₅alkanoyloxy which is interrupted byoxygen, sulfur or

[0153] C₁-C₂₅alkanoylamino, C₃-C₂₅alkenoyl; C₃-C₂₅alkenoyl which isinterrupted by oxygen, sulfur or

[0154] C₃-C₂₅-alkenoyloxy; C₃-C₂₅alkenoyloxy which is interrupted byoxygen, sulfur or

[0155] C₆-C₉-cycloalkylcarbonyl, C₆-C₉cycloalkylcarbonyloxy, benzoyl orC₁-C₁₂alkyl-substituted benzoyl; benzoyloxy or C₁-C₁₂alkyl-substitutedbenzoyloxy;

[0156] or

[0157] or also, in formula 9, R₇ and R₈, or R₈ and R₁₁, together withthe linking carbon atoms, are a benzene ring,

[0158] R₁₂ and R₁₃ are each independently of the other unsubstituted orC₁-C₄alkyl-substituted phenylene or naphthylene,

[0159] R₁₄ is hydrogen or C₁-C₈alkyl,

[0160] R₅ is hydroxy,$\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack$

[0161] C₁-C₁₈alkoxy or

[0162] R₁₆ and R₁₇ are each independently of the other hydrogen, CF₃,C₁-C₁₂alkyl or phenyl, or R₁₆ and R₁₇, together with the linking carbonatom, are a C₅-C₈cycloalkylidene ring which is unsubstituted orsubstituted by 1 to 3 C₁-C₄alkyl;

[0163] R₁₈ and R₁₉ are each independently of the other hydrogen,C₁-C₄alkyl or phenyl,

[0164] R₂₀ is hydrogen or C₁-C₄alkyl,

[0165] R₂₁ is hydrogen, unsubstituted or C₁-C₄alkyl-substituted phenyl;C₁-C₂₅alkyl; C₂-C₂₅alkyl which is interrupted by oxygen, sulfur or

[0166] C₇-C₉phenylalkyl which is unsubstituted or substituted at thephenyl radical by 1 to 3 C₁-C₄alkyl; C₇-C₂₅phenylalkyl which isinterrupted by oxygen, sulfur or

[0167] which is unsubstituted or substituted at the phenyl radical by 1to 3 C₁-C₄alkyl, or R₂₀ and R₂₁, together with the linking carbon atoms,are a C₅-C₁₂cycloalkylene ring which is unsubstituted or substituted by1 to 3 C₁-C₄alkyl;

[0168] R₂₂ is hydrogen or C₁-C₄alkyl,

[0169] R₂₃ is hydrogen, C₁-C₂₅alkanoyl, C₃-C₂₅alkenoyl; C₃-C₂₅alkanoylwhich is interrupted by oxygen, sulfur or

[0170] C₂-C₂₅alkanoyl which is substituted by adi(C₁-C₆alkyl)phosphonate group; C₆-C₉cycloalkylcarbonyl, thenoyl,furoyl, benzoyl or C₁-C₁₂alkyl-substituted

[0171] R₂₄ and R₂₅ are each independently of the other hydrogen orC₁-C₁₈alkyl,

[0172] R₂₆ is hydrogen or C₁-C₈alkyl,

[0173] R₂₇ is a direct bond, C₁-C₁₈alkylene; C₂-C₁₈alkylene which isinterrupted by oxygen, sulfur or

[0174] C₂-C₁₈alkenylene, C₂-C₂₀alkylidene, C₇-C₂₀phenylalkylidene,C₅-C₈cycloalkylene, C₇-C₈bicycloalkylene, unsubstituted orC₁-C₄alkyl-substituted phenylene,

[0175] R₂₈ is hydroxy,$\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

[0176] C₁-C₁₈alkoxy or

[0177] R₂₉ is oxygen, —NH— or

[0178] R₃₀ is C₁-C₁₈alkyl or phenyl,

[0179] R₃₁ is hydrogen or C₁-C₁₈alkyl,

[0180] M is an r-valent metal cation,

[0181] X is a direct bond, oxygen, sulfur or —NR₃₁—,

[0182] n is 1 or 2,

[0183] p is 0, 1 or 2,

[0184] q is 1, 2, 3, 4, 5 or 6,

[0185] r is 1, 2 or 3, and

[0186] s is 0, 1 or 2.

[0187] Benzofuran-2-ones of particular technical interest are thosewhich are listed hereinafter in the list of possible costabilisers underitem 14.

[0188] Furthermore, this invention relates to a composition, whichcomprises

[0189] a)pentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate),and

[0190] b) at least one compound of the benzofuran-2-one type.

[0191] The novel compositions containpentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)(component a) preferably in amorphous form. Particularly preferredcompositions are those, which comprise components a and b side by sidein the same amorphous phase. The inventive stabiliser compositionsusually contain less than 10% by weight of high molecular weight orpolymeric components, typically those having a molecular weight of 1500g/mol or higher; there are mostly no such high molecular weightcomponents present.

[0192] Use as stabiliser for organic material

[0193] The products of the process of this invention, the novelamorphous compounds, the colour-stabilised compound 13 according to thisinvention, and also the novel β-crystalline modification of compound 14are particularly suitable for stabilising organic materials againstdamage by light, oxygen or heat.

[0194] The materials to be stabilised may be, for example, oils, fats,paint systems, cosmetics, photographic materials or biocides.Particularly interesting is the use in polymeric materials, as is thecase in plastics, rubbers, coating materials, photographic material orsizes. When used in cosmetic preparations, the material to be protectedis often not the preparation itself, but the skin or hair to which thepreparation is applied.

[0195] Illustrative examples of polymers and other substrates which canbe stabilised in this manner are:

[0196] 1. Polymers of monoolefins and diolefins, for examplepolypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene,polyisoprene or polybutadiene, as well as polymers of cycloolefins, forinstance of cyclopentene or norbornene, polyethylene (which optionallycan be crosslinked), for example high density polyethylene (HDPE), highdensity and high molecular weight polyethylene (HDPE-HMW), high densityand ultrahigh molecular weight polyethylene (HDPE-UHMW), medium densitypolyethylene (MDPE), low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), (VLDPE) and (ULDPE). Polyolefins, i.e. thepolymers of monoolefins exemplified in the preceding paragraph,preferably polyethylene and polypropylene, can be prepared by different,and especially by the following, methods:

[0197] a) radical polymerisation (normally under high pressure and atelevated temperature).

[0198] b) catalytic polymerisation using a catalyst that normallycontains one or more than one metal of groups IVb, Vb, VIb or VIII ofthe Periodic Table. These metals usually have one or more than oneligand, typically oxides, halides, alcoholates, esters, ethers, amines,alkyls, alkenyls and/or aryls that may be either π- or σ-coordinated.These metal complexes may be in the free form or fixed on substrates,typically on activated magnesium chloride, titanium(III) chloride,alumina or silicon oxide. These catalysts may be soluble or insoluble inthe polymerisation medium. The catalysts can be used by themselves inthe polymerisation or further activators may be used, typically metalalkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metalalkyloxanes, said metals being elements of groups Ia, IIa and/or IIIa ofthe Periodic Table. The activators may be modified conveniently withfurther ester, ether, amine or silyl ether groups. These catalystsystems are usually termed Phillips, Standard Oil Indiana, Ziegler(-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).

[0199] 2. Mixtures of the polymers mentioned under 1), for examplemixtures of polypropylene with polyisobutylene, polypropylene withpolyethylene (for example PP/HDPE, PP/LDPE) and mixtures of differenttypes of polyethylene (for example LDPE/HDPE).

[0200] 3. Copolymers of monoolefins and diolefins with each other orwith other vinyl monomers, for example ethylene/propylene copolymers,linear low density polyethylene (LLDPE) and mixtures thereof with lowdensity polyethylene (LDPE), propylene/but-1-ene copolymers,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/methylpentene copolymers,ethylene/heptene copolymers, ethylene/octene copolymers,propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylatecopolymers, ethylene/vinyl acetate copolymers and their copolymers withcarbon monoxide or ethylene/acrylic acid copolymers and their salts(ionomers) as well as terpolymers of ethylene with propylene and a dienesuch as hexadiene, dicyclopentadiene or ethylidene-norbornene; andmixtures of such copolymers with one another and with polymers mentionedin 1) above, for example polypropylene/ ethylene-propylene copolymers,LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acidcopolymers (EM), LLDPE/EVA, LLDPE/EAA and alternating or randompolyalkylene/carbon monoxide copolymers and mixtures thereof with otherpolymers, for example polyamides.

[0201] 4. Hydrocarbon resins (for example C₅-C₉) including hydrogenatedmodifications thereof (e.g. tackifiers) and mixtures of polyalkylenesand starch.

[0202] 5. Polystyrene, poly(p-methylstyrene), poly(a-methylstyrene).

[0203] 6. Copolymers of styrene or α-methylstyrene with dienes oracrylic derivatives, for example styrene/butadiene,styrene/acrylonitrile, styrene/alkyl methacrylate,styrene/butadiene/alkyl acrylate, styrene/butadiene/alkyl methacrylate,styrene/maleic anhydride, styrene/acrylonitrile/methyl acrylate;mixtures of high impact strength of styrene copolymers and anotherpolymer, for example a polyacrylate, a diene polymer or anethylene/propylene/diene terpolymer; and block copolymers of styrenesuch as styrene/butadiene/styrene, styrene/isoprene/styrene,styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene.

[0204] 7. Graft copolymers of styrene or α-methylstyrene, for examplestyrene on polybutadiene, styrene on polybutadiene-styrene orpolybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (ormethacrylonitrile) on polybutadiene; styrene, acrylonitrile and methylmethacrylate on polybutadiene; styrene and maleic anhydride onpolybutadiene; styrene, acrylonitrile and maleic anhydride or maleimideon polybutadiene; styrene and maleimide on polybutadiene; styrene andalkyl acrylates or methacrylates on polybutadiene; styrene andacrylonitrile on ethylene/propylene/diene terpolymers; styrene andacrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styreneand acrylonitrile on acrylate/butadiene copolymers, as well as mixturesthereof with the copolymers listed under 6), for example the copolymermixtures known as ABS, MBS, ASA or AES polymers.

[0205] 8. Halogen-containing polymers such as polychloroprene,chlorinated rubbers, chlorinated and brominated copolymer ofisobutylene-isoprene (halobutyl rubber), chlorinated or sulfochlorinatedpolyethylene, copolymers of ethylene and chlorinated ethylene,epichlorohydrin homo- and copolymers, especially polymers ofhalogen-containing vinyl compounds, for example polyvinyl chloride,polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluride, aswell as copolymers thereof such as vinyl chloride/vinylidene chloride,vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetatecopolymers.

[0206] 9. Polymers derived from α,β-unsaturated acids and derivativesthereof such as polyacrylates and polymethacrylates; polymethylmethacrylates, polyacrylamides and polyacrylonitriles, impact-modifiedwith butyl acrylate.

[0207] 10. Copolymers of the monomers mentioned under 9) with each otheror with other unsaturated monomers, for example acrylonitrile/ butadienecopolymers, acrylonitrile/alkyl acrylate copolymers,acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halidecopolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

[0208] 11. Polymers derived from unsaturated alcohols and amines or theacyl derivatives or acetals thereof, for example polyvinyl alcohol,polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinylmaleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine;as well as their copolymers with olefins mentioned in 1) above.

[0209] 12. Homopolymers and copolymers of cyclic ethers such aspolyalkylene glycols, polyethylene oxide, polypropylene oxide orcopolymers thereof with bisglycidyl ethers.

[0210] 13. Polyacetals such as polyoxymethylene and thosepolyoxymethylenes which contain ethylene oxide as a comonomer;polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

[0211] 14. Polyphenylene oxides and sulfides, and mixtures ofpolyphenylene oxides with styrene polymers or polyamides.

[0212] 15. Polyurethanes derived from hydroxyl-terminated polyethers,polyesters or polybutadienes on the one hand and aliphatic or aromaticpolyisocyanates on the other, as well as precursors thereof.

[0213] 16. Polyamides and copolyamides derived from diamines anddicarboxylic acids and/or from aminocarboxylic acids or thecorresponding lactams, for example polyamide 4, polyamide 6, polyamide6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromaticpolyamides starting from m-xylene diamine and adipic acid; polyamidesprepared from hexamethylenediamine and isophthalic or/and terephthalicacid and with or without an elastomer as modifier, for examplepoly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenyleneisophthalamide; and also block copolymers of the aforementionedpolyamides with polyolefins, olefin copolymers, ionomers or chemicallybonded or grafted elastomers; or with polyethers, e.g. with polyethyleneglycol, polypropylene glycol or polytetramethylene glycol; as well aspolyamides or copolyamides modified with EPDM or ABS; and polyamidescondensed during processing (RIM polyamide systems).

[0214] 17. Polyureas, polyimides, polyamide-imides, polyetherimids,polyesterimids, polyhydantoins and polybenzimidazoles.

[0215] 18. Polyesters derived from dicarboxylic acids and diols and/orfrom hydroxycarboxylic acids or the corresponding lactones, for examplepolyethylene terephthalate, polybutylene terephthalate,poly-1,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates,as well as block copolyether esters derived from hydroxyl-terminatedpolyethers; and also polyesters modified with polycarbonates or MBS.

[0216] 19. Polycarbonates and polyester carbonates.

[0217] 20. Polysulfones, polyether sulfones and polyether ketones.

[0218] 21. Crosslinked polymers derived from aldehydes on the one handand phenols, ureas and melamines on the other hand, such asphenol/formaldehyde resins, urea/formaldehyde resins andmelamine/formaldehyde resins.

[0219] 22. Drying and non-drying alkyd resins.

[0220] 23. Unsaturated polyester resins derived from copolyesters ofsaturated and unsaturated dicarboxylic acids with polyhydric alcoholsand vinyl compounds as crosslinking agents, and also halogen-containingmodifications thereof of low flammability.

[0221] 24. Crosslinkable acrylic resins derived from substitutedacrylates, for example epoxy acrylates, urethane acrylates or polyesteracrylates.

[0222] 25. Alkyd resins, polyester resins and acrylate resinscrosslinked with melamine resins, urea resins, isocyanates,isocyanurates, polyisocyanates or epoxy resins.

[0223] 26. Crosslinked epoxy resins derived from aliphatic,cycloaliphatic, heterocyclic or aromatic glycidyl compounds, e.g.products of diglycidyl ethers of bisphenol A and bisphenol F, which arecrosslinked with customary hardeners such as anhydrides or amines, withor without accelerators.

[0224] 27. Natural polymers such as cellulose, rubber, gelatin andchemically modified homologous derivatives thereof, for examplecellulose acetates, cellulose propionates and cellulose butyrates, orthe cellulose ethers such as methyl cellulose; as well as rosins andtheir derivatives.

[0225] 28. Blends of the aforementioned polymers (polyblends), forexample PP/EPDM, polyamide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS,PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates,POM/thermoplastic PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS,PPO/HIPS, PPO/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPO, PBT/PC/ABSor PBT/PET/PC.

[0226] This invention therefore also relates to a composition, whichcomprises

[0227] A) an organic material susceptible to oxidative, thermal or/andactinic degradation or build-up, and

[0228] B) the amorphous form of one of the compounds No. 1-12, 14, 18,the colour-stabilised amorphous compound 13 and/or the β-crystallineform of the compound 14 as stabiliser, as well as to the use of theamorphous form of one of the compounds No. 1-12, 14, 18, of thecolour-stabilised amorphous compound 13 and/or of the β-crystalline formof compound 14 for stabilising organic material against oxidative,thermal or actinic degradation or build-up.

[0229] Component B is preferably the amorphous form of one of thecompounds No. 1-12, 14, 18 and also the β-crystalline form of compound14.

[0230] The invention also relates to a process for stabilising organicmaterial against thermal, oxidative or/and actinic degradation orbuild-up, which comprises applying the amorphous form of one of thecompounds No. 1-12, 14, 18, the colour-stabilised amorphous compound 13and/or the β-crystalline form of compound 14 to this material and/orpreferably adding them thereto, as well as to the corresponding use. Theamorphous form of one of the compounds No. 1-12, 14, 18, thecolour-stabilised amorphous compound 13 and/or the β-crystalline form ofcompound 14 can be used here by itself or as component of a mixture ofthe amorphous form of one or several compounds No. 1-12, 14, 18, of thecolour-stabilised amorphous compound 13 and/or of the β-crystalline formof compound 14 with the conventional crystalline form and/or otherconventional additives.

[0231] The amount of the stabiliser (amorphous and, if required,crystalline) to be used in total depends on the organic material to bestabilised and on the intended use of the stabilised material. The novelcomposition generally comprises, per 100 parts by weight of component A,0.01 to 15, preferably 0.05 to 10 and, more preferably, 0.1 to 5, partsby weight of the novel stabiliser (novel amorphous modification of oneof the compounds No. 1-12, 14, 18, colour-stabilised amorphous compound13 and/or β-crystalline form of compound 14 or mixture comprising anovel amorphous or β-crystalline modification).

[0232] Particularly interesting is the use of the novel stabiliser insynthetic organic polymers as well as corresponding compositions, inparticular thermoplastic polymers which are processed at elevatedtemperatures, for example by extruding, blow moulding, calendering,injection moulding, casting, compressing, sintering, spinning, foaming,soldering, laminating, heat-moulding, and the like.

[0233] The organic materials to be protected are preferably natural,semi-synthetic or synthetic organic materials.

[0234] The novel stabiliser can be used particularly advantageously incompositions which comprise as component A a synthetic organic polymer,preferably a thermoplastic polymer or a binder for coatings, such aspaint systems. Suitable thermoplastic polymers are, for example,polyolefins, preferably polyethylene (PE) and polypropylene (PP), aswell as those polymers which contain hetero atoms in the main chain.

[0235] In a preferred aspect, this invention also relates to acomposition wherein the novel modification is incorporated in athermoplastic polymer, in a paint binder, in particular one based on anacrylic, alkyd, polyurethane, polyester or polyamide resin orcorresponding modified resins, or in a photographic material. Thematerial to be protected (component A) can in this case be athermoplastic polymer, a paint binder, in particular based on anacrylic, alkyd, polyurethane, polyester or polyamide resin orcorresponding modified resins, a photographic material, or a colourantpresent in this material.

[0236] Particularly interesting is also the use of the novelmodifications as stabiliser for coatings, for example for paint systems.

[0237] The incorporation in the materials to be stabilised can, forexample, be carried out by admixing or applying the novel stabiliserand, if required, other additives, by the customary methods of the art.In the case of polymers, in particular of synthetic polymers, theincorporation can be carried out before or after moulding, or byapplying the dissolved or dispersed compound to the polymer, if requiredwith subsequent evaporation of the solvent. Elastomers can also bestabilised as latices. Another possibility of incorporating the novelstabiliser in polymers consists in their addition before, during orimmediately after the polymerisation of the corresponding monomers orbefore crosslinking. The amorphous or β-crystalline compound can in thiscase be added as such or also in encapsulated form (e.g. in waxes, oilsor polymers). If the stabiliser is added before or during thepolymerisation, it can also serve as chain length regulator (chainterminator) for the polymers.

[0238] The novel stabiliser can also be added to the plastics to bestabilised in the form of a master-batch which comprises the stabilisere.g. in a concentration of 2.5 to 25% by weight.

[0239] The incorporation of the novel stabiliser may conveniently becarried out by the following methods:

[0240] as emulsion or dispersion (e.g. to latices or emulsion polymers),

[0241] as dry mixture before mixing additive components or polymermixtures,

[0242] by direct addition to the processing apparatus (e.g. extruder,internal mixer, etc.)

[0243] as solution or melt.

[0244] The novel stabiliser is preferably added to the polymer before orafter processing, preferably as dry mixture during the mixing ofadditive components or polymer mixtures, or by direct addition to theprocesssing apparatus.

[0245] Polymer compositions of this invention can be used in differentform or can be processed to different products, e.g. foils, fibres,filaments, moulding compositions, profiles, or binders for paintsystems, sizes or putties.

[0246] In addition to the novel stabiliser, the novel compositions cancomprise as additional component (C) one or several conventionaladditives, such as antioxidants, further light stabilisers, metaldeactivators, phosphites or phosphonites. Illustrative examples thereofare:

[0247] 1. Antioxidants

[0248] 1.1. Alklated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-di-methylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linearor branched in the side chains, for example,2,6-di-nonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures thereof.

[0249] 1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

[0250] 1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

[0251] 1.4. Tocopherols, for example α-tocopherol, β-tocopherol,γ-tocopherol, ε-tocopherol and mixtures thereof (Vitamin E).

[0252] 1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis-(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.

[0253] 1.6. Alkylidenebisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

[0254] 1.7. O-, N- and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

[0255] 1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate,didodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

[0256] 1.9. Aromatic hydroxybenzyl compounds, for example1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

[0257] 1.10. Triazine compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

[0258] 1.11. Benzylphosphonates, for exampledimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate,diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, thecalcium salt of the monoethyl ester of3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

[0259] 1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

[0260] 1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionicacid with mono- or polyhydric alcohols, e.g. with methanol, ethanol,n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

[0261] 1.14. Esters ofβ-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- orpolyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis-(hydroxyethyl)oxamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

[0262] 1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionicacid with mono- or polyhydric alcohols, e.g. with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

[0263] 1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

[0264] 11.17. Amides of β-(3,5-di-tert-butyl-4-hydroxylphenyl)propionicacid e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide,N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide(Naugard®XL-1 supplied by Uniroyal).

[0265] 1.18. Ascorbic acid (vitamin C)

[0266] 1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenlenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxy diphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyl-diphenylamines, a mixture of mono- anddialkylated nonyldiphenylamines, a mixture of mono- and dialkylateddodecyldiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamines, a mixture of mono- und dialkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- und dialkylatedtert-butyl/tert-octylphenothiazines, a mixture of mono- und dialkylatedtert-octyl-phenothiazines, N-allylphenothiazin,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis-(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl)-sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

[0267] 2. UV absorbers and light stabilisers

[0268] 2.1. 2-(2′-Hydroxyphenyl)benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl- 2′-hydroxy-5′-methylphenyl)-5-chloro-benzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotrazole,2-(3′,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)-carbonylethyl]-2′-hydroxyphenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylene-bi44-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol];the transesterification product of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300; [R—CH₂CH₂—COO—CH₂CH₂—]₂ whereR=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl,2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)phenyl]-benzotriazole;2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)-5′-(α,α-dimethylbenzyl)phenyl]-benzotriazole.

[0269] 2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy,4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy,4,2′,4′-trihydroxy and 2′-hydroxy-4,4′-dimethoxy derivatives.

[0270] 2.3. Esters of substituted and unsubstituted benzoic acids, asfor example 4-tertbutyl-phenyl salicylate, phenyl salicylate,octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

[0271] 2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate,isooctyl α-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate,methyl α-cyano-β-methyl-p-methoxy-cinnamate, butylα-cyano-β-methyl-p-methoxy-cinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

[0272] 2.5. Nickel compounds, for example nickel complexes of2,2′-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. themethyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenylundecylketoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additionalligands.

[0273] 2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl)succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cycliccondensates ofN,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,3-dodecyl-1 -(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decane und epichlorohydrin,1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,diester of 4-methoxymethylene-malonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane,reaction product of maleic acid anhydride-α-olefin-copolymer with2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

[0274] 2.7. Oxamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanlide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, mixtures of o- andp-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

[0275] 2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxy-propoxy)phenyl]-1,3,5-triazine,2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine,2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

[0276] 3. Metal deactivators, for example N,N′-diphenyloxamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

[0277] 4. Phosphites and phosphonites, for example triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite,diisodecyloxypentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylene diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite,2,2′,2″-nitrilo[triethyltris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite.

[0278] Especially preferred are the following phosphites:

[0279] Tris(2,4di-tert-butylphenyl) phosphite (Irgafos®168, Ciba-Geigy),tris(nonylphenyl) phosphite,

[0280] 5. Hydroxylamines, for example N,N-dibenzylhydroxylamine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dhexadecylhydroxylamine, N,N-dioctadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derivedfrom hydrogenated tallow amine.

[0281] 6. Nitrones, for example N-benzyl-alpha-phenyl-nitrone,N-ethyl-alpha-methyl-nitrone, N-octyl-alpha-heptyl-nitrone,N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridcyl-nitrone,N-hexadecyl-alpha-pentadecyl-nitrone,N-octadecyl-alpha-heptadecyl-nitrone,N-hexadecyl-alpha-heptadecyl-nitrone,N-ocatadecyl-alpha-pentadecyl-nitrone,N-heptadecyl-alpha-heptadecyl-nitrone,N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived fromN,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

[0282] 7. Thiosynergists, for example dilauryl thiodipropionate ordistearyl thiodipropionate.

[0283] 8. Peroxide scavengers, for example esters of β-thiodipropionicacid, for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

[0284] 9. Polyamide stabilisers, for example copper salts in combinationwith iodides and/or phosphorus compounds and salts of divalentmanganese.

[0285] 10. Basic co-stabilisers, for example melamine,polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, ureaderivatives, hydrazine derivatives, amines, polyamides, polyurethanes,alkali metal salts and alkaline earth metal salts of higher fatty acids,for example, calcium stearate, zinc stearate, magnesium behenate,magnesium stearate, sodium ricinoleate and potassium palmitate, antimonypyrocatecholate or zink pyrocatecholate.

[0286] 11. Nucleating agents, for example inorganic substances such astalcum, metal oxides such as titanium dioxide or magnesium oxide,phosphates, carbonates or sulfates of, preferably, alkaline earthmetals; organic compounds such as mono- or polycarboxylic acids and thesalts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid,diphenylacetic acid, sodium succinate or sodium benzoate; polymericcompounds such as ionic copolymers (ionomers).

[0287] 12. Fillers and reinforcing agents, for example calciumcarbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin,mica, barium sulfate, metal oxides and hydroxides, carbon black,graphite, wood flour and flours or fibers of other natural products,synthetic fibers.

[0288] 13. Other additives, for example plasticisers, lubricants,emulsifiers, pigments, rheology additives, catalysts, flow-controlagents, optical brighteners, flameproofing agents, antistatic agents andblowing agents.

[0289] 14. Benzofuranones and indolinones, for example those disclosedin U.S. Pat. No. 4,325,863; U.S. Pat. No. 4,338,244; U.S. Pat. No.5,175,312; U.S. Pat. No. 5,216,052; U.S. Pat. No. 5,252,643;DE-A-4316611; DE-A-4316622; DE-A-4316876; EP-A-0589839 or EP-A-0591102or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butylbenzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

[0290] The type and amount of the further stabilisers added isdetermined by the type of substrate to be stabilised and by itsenvisaged use; often, 0.0005-10, for example 0.001-5, preferably0.01-2.5%, by weight, based on the material to be stabilised, are added.

[0291] It is particularly advantageous to use the novel modifications ofcompounds No. 1, 10, 11 and/or 14 in combination with stericallyhindered amines, for example 2,2,6,6-tetralkylpiperidine derivatives.This invention therefore relates to a synergistic stabiliser mixture,which comprises (a) the β-crystalline modification of compound 14 and/orthe amorphous modification of compound No. 1, 10, 11, and/or 14, and

[0292] (b) at least one sterically hindered amine, the salt thereof withany acid or the complex thereof with a metal, as well as to acomposition, which comprises

[0293] A) an organic material susceptible to oxidative, thermal or/andactinic degradation or build-up,

[0294] B) the β-crystalline modification of compound 14 and/or theamorphous modification of compound No. 1, 10, 11, and/or 14, and also

[0295] C) a conventional additive of the sterically hindered amine type.

[0296] Preferred sterically hindered amines are, for example, thosewhich are given in the above list under item 2.6.

[0297] It is also particularly advantageous to use the novelmodifications in combination with costabilisers of the2-(2-hydroxyphenyl)-1,3,5-triazine type, as exemplified in the abovelist under item 2.8.

[0298] The invention is illustrated by the following Examples. In theExamples as well as in the remaining description and in the patentclaims, all parts or percentages are by weight, unless otherwise stated.The temperatures are determined by differential thermoanalysis [DSC] ata heating rate of 4° C./min (m.p.) or 20° C./min (T_(G)), unlessotherwise stated.

[0299] In the Examples, compound A isbis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate. In the Examples,compound B is a commercially available mixture of different phosphonites(CAS-no. 119345-01-6) having the main components

[0300] The following abbreviations are used in the Examples and Tables:

[0301] DSC: differential scanning calorimetry (quantitative dynamicdifferential thermoanalysis)

[0302] Tg or T_(G) glass transition temperature (DSC, +20° C./min)

[0303] h, min: hour(s), minute(s)

[0304] m.p. melting point (DSC, +4° C./min)

EXAMPLE 1 Preparation of the Amorphous Form of Compound No. 1 onLaboratory Scale

[0305] A 30 ml boiling glass is charged with 10 g of crystallinepowdered2,2′-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol)(compound No. 1) which is heated under nitrogen indirectly via spoonsieve and controllable hot blast (air temperature 235-245° C.). At 200°C., the powder turns into a pale yellow, clear and low viscous meltwhich is tempered at 205° C.

[0306] After pouring the melt in portions on a stainless steel platecooled to 15° C. with water, the melt quickly becomes highly viscous andsolidifies spontaneously. Pellets are prepared from part of the melt bydripping on the cooled steel plate. The vitreous composition can beeasily separated from the cooling plate and pulverised in a mortar. DSC(heating rate 20° C./min.) confirms the amorphous structure,T_(g)=72-75° C.

EXAMPLE 1a Preparation of the Amorphous Form of Compounds 1-12, 18, 19on Laboratory Scale

[0307] As described in Example 1, a 30 ml boiling glass is charged with10 g each of crystalline powdered compound which is heated undernitrogen indirectly via spoon sieve and controllable hot blast. AtT>melting point (m.p.), the powder turns into a colourless or veryslightly coloured clear and low viscous melt which is tempered at Ti.

[0308] After pouring the melt in portions on a stainless steel platecooled to Tw with water, the melt quickly becomes highly viscous andsolidifies spontaneously. Pellets are formed from part of the melt bydripping on the cooled steel plate. The vitreous composition can beeasily separated from the cooling plate and, if desired, can be powderedat T<Tg in a mortar.

[0309] The following Table provides molecular weight, melting point(m.p.) of the crystalline form and glass transition temperature (Tg;Cp-leap according to DSC) of the amorphous form: molec. weight m.p. TiTw Tg No. g/mol ° C. ° C. ° C. ° C. (+ 20° C./min)  1) 658 197 205 1573-74  2) 358 161 185 15 30-31  3) 594.8 177 190 15 59-60  4) 636.9 160185 15 54-55  5) 775 179; 243 250 15 97-98  6) 784 220 225 15 109-110 7) 553 200; 221 225 15 69-70  8) 699 158 170 15 115-120  9) 685 148 16515 44-45 10) 447.6 139 160 10 41-42 11) 323.4 154 170  5 19-20 12) 350.5132 145 10 24-25 18) 552 163 170 10 52-55 19) 441.4 113 120 15 33-34

[0310] The novel amorphous modifications of the above compounds give alinefree X-ray diffraction diagram with Cu-kα-radiation. The novelamorphous form is solid below T_(G) and plastic above T_(G).

[0311] Typical data for the viscosity of the plastic amorphous form at130° C. and of the known melt of compound (1) (liquid state, 200° C.) atdifferent shearing speeds D are found in the following Table; the datahave been determined using a rotary viscosimeter of the typeRheomat-30/Rheotemp, measuring system cone and plate.

[0312] Tab.: Viscosity (Pa.s) of cmpd.(1) in the plastic state (130° C.)and in the liquid state (200° C.) D = 1 s⁻¹ D = 3 s⁻¹ D = 60 s⁻¹ plastic40 40 20 liquid 0.4 0.13

EXAMPLE 2 Preparation of Amorphous Pellets

[0313] The melt of compound No. 1 is dripped at 200-205° C. and at 20kg/h throughput via a device of the type SANDVIK-Rotoformer® (feed width0.25 m) and is pelletised on a 4.5 m long cooling conveyor tempered to15-25° C. with water. The required cooling time is varied in the rangefrom 8 s to 60 s via the conveyor speed; the drop diameter is 1 mm (8 scooling time) to 4 mm (60 s cooling time).

[0314] Amorphous pellets are obtained which have the propertiesdescribed in Example 1.

EXAMPLE 2a

[0315] A melt of one of the compounds 2, 3, 4, 5, 6, 7, 8, 9, 18 or 19each is processed by the method described in Example 2. Amorphouspellets are obtained having the properties described in Example 1a.

EXAMPLE 3 Use of Compound (1) in the Novel Extrusion Process

[0316]2,2′-Methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol)is added gravimetrically in powdered form at a throughput of 19 kg/h toa laboratory twin-screw extruder (Bühler, Typ DNDL 44). The screwdiameter is 44 mm, the ratio length/diameter (UD) is 40 at 10 barrels,rotational speed of the screw 130 min⁻¹.

[0317] The laboratory extruder is heated as follows:

[0318] barrel 1 (powder addition): cooling water (15° C.), barrels2/3/4: oil at 205° C., barrels 5/6/7: oil at 210° C., barrels 8/9/10:hydraulic water at 120° C.

[0319] Under these conditions, the powder is melted to about 70% up tobarrel 7. The paste which is initially low viscous cools quickly to 130°C. from barrel 8 onwards (subcooled melt component about 30%). At adynamic pressure of 11 bar, cuttable strands are obtained behind theheated die plate (223° C.; 2 free holes of 2.5 mm each). Hot-cut viarotating knife at a cutting frequency of 123 s⁻¹ gives soft granuleswhich are subcooled in a fluidised bed cooler with subsequentcrystallisation with air. The following properties are found: particlesize (minimum-maximum 2-5 mm dimension): bulk density: 510-590 kg/langle of repose (DIN-ISO norm 4324): 40° flow time (DIN norm 53492): 2.7s (φ = 25 mm) evolution of dust (Heubach test): <0.1 G% after 5 mincrystallinity (DSC): about 95-99%

EXAMPLE 4 Stabilisation of Polycarbonate (PC)

[0320] 4985 g of polycarbonate powder (Lexan®145, producer: GeneralElectric) are mixed with 15 g of the novel stabiliser (product ofExample 1, powdered) in a Henschel mixer at room temperature. The powdermixture so obtained is processed to granules using a GöttfertExtrusiometer MP 2.3.0 at a temperature setting of 260/270/280/280° C.at 60 rpm and at a pressure of 61.5 bar and at a shear strength of 47.3Nm.

[0321] 2 mm thick plates are produced from the granules so obtained byan injection moulding process (temperature of the die 300° C.,temperature of the melt 120° C.).

[0322] The plates are exposed to light in an Atlas Weatherometer C165under the following conditions:

[0323] black standard temperature 63° C.,

[0324] relative moisture 60% (dry phase),

[0325] cycle 102 min. dry/18 min. wet,

[0326] irradiation 0.35 W/m² at 340 nm.

[0327] The discoloration of the samples is examined before weathering isstarted, and then at regular intervals, by measuring the yellownessindex (YI, method ASTM D 1925). The results are compiled in Table 1;YI(0) indicates the initial colour (=yellowness index before weatheringis started). TABLE 1: yellowness index YI and embrittlement before andduring weathering weathering time/h stabiliser 0 500 950 1214 0.3% 6.56.7 11.5 16.1

EXAMPLE 5 Preparation of Solid Single-phase Amorphous Mixtures

[0328] Mixtures of2,2′-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-yl-phenol)(compound 1) and tris(2,4-di-tert-butylphenyl)phosphite (m.p. 180-185°C.) at a weight ratio of 10:1 and 5:1 are melted and chilled by themethod described in Example 1.

[0329] This gives single-phase amorphous mixtures, T_(G)=65-67° C.(mixture 10:1) and T_(G)=61-63° C. (mixture 5:1) (compare the followingTable, samples a and b).

[0330] Other single-phase amorphous mixtures are obtained by the abovemethod, 10 g each of a powdered mixture being placed in a boiling glassand homogenised during the melting process under nitrogen at thetemperature Ti. The mixtures are then chilled via a surface cooled to Twunder standard atmosphere. The compound used, the test parameters andthe resulting glass transition temperature Tg of the amorphous mixtureare compiled in the following Table (amounts are given in percent byweight, based on the total weight of the mixture): Sam- Ti Tw Tg pleCompounds and amount (° C.) (° C.) (° C.) a) 9.1% cmpd. 16, 90.9% cmpd.1 205 18 65-67 b) 16.7% cmpd. 16, 83.3% cmpd. 1 205 18 61-63 c) 16.7%cmpd. 16, 83.3% cmpd. 5 245 18 76-80 d) 50% cmpd. 16, 50% cmpd. 6 220 1562-63 e) 33.3% cmpd. 16 66.7% cmpd. 6 225 15 76-79 f) 50% cmpd. 13 50%cmpd. 2 165 15 48-49 g) 50% cmpd. 13 50% cmpd. 4 165 15 49-51 h) 50%cmpd. 13 50% cmpd. 3 180 15 52-54 i) 50% cmpd. 13 50% cmpd. 5 245 1562-63 j) 50% cmpd. 13 50% cmpd. 6 220 15 67-68 k) 50% cmpd. 13 50% cmpd.7 230 15 65-66 l) 50% cmpd. 13 50% cmpd. 10 140 15 45-46 m) 50% cmpd. 1350% cmpd. 9 150 15 46-47 n) 50% cmpd. 13 50% cmpd. 11 150 15 34-36 o)50% cmpd. 13 50% cmpd. 1 200 15 56-57 o1) 50% cmpd. 13 50% cmpd. 12 13513 33-34 o2) 50% cmpd. 13 50% cmpd. 19 125 13 42-44 o3) 50% cmpd. 13 50%cmpd. 15 205 18 60-61 o4) 50% cmpd. 13 50% cmpd. B 135 18 40-41 o5) 10%cmpd. 13 90% cmpd. 16 195 15 39-40 o6) 30% cmpd. 13 70% cmpd. 16 190 1539-40 o7) 50% cmpd. 13 50% cmpd. 16 190 15 41-42 o8) 70% cmpd. 13 30%cmpd. 16 170 15 44-45 o9) 90% cmpd. 13 10% cmpd. 16 140 15 45-46 p)33.3% cmpd. A 66.7% cmpd. 6 220 15 35-36 q) 15% cmpd. 12; 28.3% cmpd.13; 200 18 38-39 56.7% cmpd. 16 r) 15% cmpd. 12; 42.5% cmpd. 13; 200 1840-41 42.5% cmpd. 16 s) 15% cmpd. 12; 56.7% cmpd. 16; 200 18 57-59 28.3%cmpd. 6 t) 15% cmpd. 12; 42.5% cmpd. 16; 225 18 56-57 42.5% cmpd. 6

EXAMPLE 5a Colour-stabilisation of Compound 13

[0331] Some of the amorphous mixtures prepared according to Example 5and comprising compound 13 are subjected to a colour stability test. Tothis purpose, the samples, which are listed in the following Table, areexposed to daylight in a closed glass vessel under atmosphericconditions. The pure amorphous compound 13 serves as comparison. Afterthe indicated storage time, the discoloration of the samples is visuallyassessed: Sample 1 Week 1 Month 2 Months Storage time cmpd. 13colourless green yellowish green f) colourless violet violet g)colourless pale green green h) colourless pale green green i) colourlesspale green yellowish green l) colourless pale green green k) colourlesspale green yellowish green n) colourless pale yellow yellow o)colourless yellow yellow o1) colourless colourless o2) colourless paleyellow yellow o3) colourless colourless colourless o4) colourlesscolourless colourless o5) colourless white* white* o6) colourless white*white* o7) colourless colourless colourless o8) colourless colourlesscolourless o9) colourless colourless q) colourless colourless r)colourless colourless

[0332] When stored, the samples o1, o3-o9, q and r which arecolour-stabilised according to this invention show a markedly lowerdiscoloration tendency than the pure compound 13 or than its mixtureswith stabilisers other than phosph(on)ites or benzofuranones.

EXAMPLE 6 Use of Subcooled Melts for the Preparation of Granules

[0333] A powdered mixture A (resp. B) consisting of compounds 13, 12 and16 (mixture ratios: see Table 6b) is added gravimetrically at athroughput of 20 kg/h to a laboratory twin-screw extruder (type BühlerDNDF 44). The screw diameter is 44 mm, the length/diameter ratio (UD) is24 at 6 barrels, rotational speed of the screws 100 min⁻¹. The barrelsof the laboratory extruder are tempered such (temperature profile: seeTable 6a), that only part of the powder (about 30% by weight) is meltedup to barrel 4 at a composition temperature of 130° C. The melt soobtained, consisting of cmpd. 13 (m.p.=115° C.) and 12 (m.p.=132° C.) ina mixture ratio 65:35 (resp. 75:25), is of low viscosity and forms onesingle microhomogeneous continuous phase, wherein cmpd. 16 (m.p.=186°C.) is dispersed as crystalline phase.

[0334] As from barrel 5, the composition is subcooled to about 65° C.(subcooled melt component 25-30% by weight) and is then forced inplastic state (Tg<T<melting point of the continuous phase) through aheated die plate having 6 free holes of 2.5 mm each at a dynamicpressure of 10-12 bar, to give cuttable strands.

[0335] Hot-cut via rotating knives at a cutting frequency of 80-100 s⁻¹(cutting length 2-2.5 mm) first gives soft granules (T>Tg), thesolidification of which is carried out in a fluidised bed coolervirtually without any subsequent crystallisation.

[0336] The granules obtained (see Table 6c) are low-dust and flowableand comprise a single-phase amorphous component (22-27% by weightaccording to DSC) consisting of cmpd. 13 (55-65% by weight) and cmpd. 12(35-45% by weight).

[0337] Another powdered mixture C (resp. D) consisting of compounds 12,16 and 6 is processed as described above for the mixtures A and B, butthe addition is carried out at a throughput of 22 kg/h and therotational speed of the screw is 50 min⁻¹. Temperature profile andmixture ratios are found in Tables 6a and 6b; the granule properties arecompiled in Table 6c. Up to barrel 4, only part of the powder (about 30%by weight) is melted at a composition temperature of about 150° C. Amelt of low viscosity consisting of cmpd. 12 (m.p. 132° C.) and 16 (m.p.186° C.) at a mixture ratio of about 50:50 is obtained as continuousphase, wherein cmpd. 6 (m.p. 220° C.) is dispersed. The composition issubcooled as from barrel 5 to about 120° C. (subcooled melt component20-25% by weight) and is processed as described above at a dynamicpressure of 7-8 bar (mixture C) or 13-15 bar (mixture D) to strandswhich are granulated at a cutting frequency of 100 s⁻¹. Compound 16 issubsequently crystallised in a fluidised bed cooler. The granules soobtained (see Table 6c) are low-dust, flowable and comprise asingle-phase amorphous component (12-15% by weight according to DSC)consisting of cmpd. 12 (about 95% by weight) and cmpd. 16 (about 5% byweight). TABLE 6a Temperature profile at the extruder; powder additionin barrel 1 Mixture A Mixture B Mixture C Mixture D barrel 1: water  18°C.  18° C.  18° C.  18° C. barrels 2 + 3: oil 140° C. 130° C. 160° C.160° C. barrel 4: oil 130° C. 130° C. 160° C. 160° C. barrel 5: water 18° C.  18° C. 100° C.  70° C. (steam) barrel 6: water  18° C.  18° C.100° C.) 105° C. (steam) (steam) die plate: oil  80° C.  80° C. 130° C.130° C.

[0338] TABLE 6b Chemical-physical composition of the granules (amountsin % by weight) cmpd. 13 cmpd. 12 cmpd. 16 cmpd. 6 total DSC analysis (°C.) mixture A: amorphous phase 13-15%  9-11% <0.5% — 22-26% Tg = 38-39crystalline phase 13-16% 4-6% >56% — 74-78% m.p.= 110; 166 total: 28.3%15% 56.7% — 100% mixture B: amorph. phase 15-18% 7-9% <0.5% — 23-27% Tg= 41-42 cryst. phase 24.5-27.5% 6-8% >42% — 73-77% m.p.= 102; 160 total:42.5% 15% 42.5% — 100% mixture C: amorphous phase — 11-12% <1% <0.5%11-13% Tg = 29-30 crystalline phase — 3-4% >56 % >28 % 87-89% m.p.= 122;160; 180-200 total: — 15% 56.7% 28.3% 100% mixture D: amorphous phase —13.5-14.5% <1% <0.5% 14-15% Tg = 30-31 crystalline phase —0.5-1.5% >41.5% >42% 75-76% m.p.= 120; 163; 170-200 total: — 15% 42.5%42.5% 100%

[0339] TABLE 6c Properties of the granules mixture: A B C and D particlesize (mm; 1.5-3.5 1.5-3.5 1.5-3.5 min.-max. dimension): bulk density(kg/l): 0.52-0.57 0.51-0.56 0.53-0.56 angle of repose (° ; 37 38 35DIN-ISO-norm 4324): flow time (s; DIN 53492; 15 mm) 10 10.5 10 formationof dust (% by weight 0.22 0.26 0.24 after 5 min; Heubach test): maximumstorage temperature (° C.): 35 35 30

EXAMPLE 7 Preparation of the β-form of Compound No. 14 by Fluidised BedGranulation

[0340] 2 kg of2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compoundNo. 14) are placed in a vessel at 190° C. in the form of a melt and aresprayed via a two-fluid nozzle on a fluidised bed consisting of 300 g ofthe ground compound 14 at an air velocity of 1-1.5 m/s. The productsolidifies with formation of granules (agglomeration), consisting tomore than 60% of β-form.

EXAMPLE 8 Preparation of the β-form of Compound 14 by Drilling

[0341] 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole(cmpd. 14) is placed in a vessel in the form of a melt and is sprayed atthe head of a prill tower and solidified in free fall via air at atemperature of below 156° C. and is then removed at the foot of thetower. The product obtained consists to more than 60% of β-form.

EXAMPLE 9 Preparation of the β-form of Compound 14 by Tempering

[0342] 100 g of2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compoundNo. 14) are kept for 15 h at 145° C. in a laboratory blade drier withoutadding any solvents. Subsequent X-ray examination shows that the productis obtained to more than 90% in the β-form.

EXAMPLE 10 Preparation of the β-form of Compound 14 by Dissolving andRecrystallisation

[0343] In a blade drier, 1600 kg of2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compound14) are charged with 240 kg of xylene and the mixture is kept for 5 h ata heating temperature of 145° C. Xylene is then removed by distillationand the contents of the drier are cooled to 100° C., charged with 100 lof water, which is then removed again by distillation, and the productis dried. The product so obtained consists completely of β-form.

[0344] On laboratory scale, 750 g of compound 14 are charged in similarmanner with 250 g of 2-butanol and 150 g of xylene and the mixture isrefluxed for 30 min, the internal temperature being 109° C., and is thenbrought to 50° C. by hot cooling, filtered and dried. The product soobtained consists completely of β-form.

EXAMPLE 11 Preparation of the Amorphous Form of Compound No. 14

[0345] 5 g of crystalline powdered2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (compound14) are placed in a 10 ml test tube and heated under nitrogen in adrying oven. The powder turns into a pale yellow, clear and low viscousmelt after 10 to 15 min at 157-159° C. The melt is poured in portions ona stainless steel plate cooled to 0° C. and quickly becomes highlyviscous and solidifies spontaneously. Pellets are prepared from part ofthe melt by dripping on the cooled steel plate. The vitreous compositioncan be easily separated from the cooling plate and powdered in a cooledmortar. DSC confirms the amorphous structure, T_(g)=22° C.

What is claimed is:
 1. A process for the preparation of a low-duststabiliser, which comprises extruding a subcooled melt consistingessentially of an organic compound having a molecular weight of 200 to1500 g/mol, or the plastic composition consisting of the mixture of thesubcooled melt and a further component, which is selected from compoundsof the subcooled melt in crystalline form and other conventionaladditives.
 2. A process according to claim 1 , wherein the molecularweight of each main component of the subcooled melt is from 300-1200g/mol.
 3. A process according to claim 1 , wherein each main componentof the subcooled melt by itself has a glass transition temperature inthe range from 10-120° C.
 4. A process according to claim 1 , whereinthe subcooled melt component in the plastic composition is from 5 to100% by weight.
 5. Granules obtained by a process according to claim 1 .6. A solid single-phase amorphous stabiliser, which comprises 2 or morecompounds having a molecular weight in the range from 300-1000 g/mol. 7.An amorphous solid or subcooled melt of2,2′-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol);bis(2-methyl-4-hydroxy-5-tert-butylphenyl)sulfide;N,N′-bis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionyl)hexamethylenediamine;1,3,5-trimethyl-2,4,6-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)benzene;1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione;1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)1,3,5-triazine-2,4,6-(1H,3H,5H)-trione;di(1,2,2,6,6-pentamethylpiperidin-4-yl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate;2-(2′-hydroxy-3′,5′-bis(1,1-dimethylbenzyl)phenyl)benzotriazole;2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole;2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole; an isomericmixture of5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-(9d)-2(3H)-benzofuranone and5,7-di-tert-butyl-3-(2,3-dimethylphenyl)-(9d)-2(3H)-benzofuranone; or ofa compound of formula


8. A mixture comprising a subcooled melt or amorphous solid of acompound according to claim 7 in an amount from 5 to 100% by weight. 9.A process for the preparation of a subcooled melt according to claim 7or of a mixture comprising a subcooled melt according to claim 8 , whichcomprises rapidly cooling the melt to a temperature from the regularmelting point to the glass transition temperature of the homogeneousphase.
 10. A process for the preparation of the amorphous solidaccording to claim 7 or of a mixture comprising an amorphous solidaccording to claim 8 , which comprises chilling the melt or subcooledmelt to a temperature below the glass transition temperature. 11.Crystalline β-modification of the compound 14

characterised by the interplanar spacings are 9.4·10⁻¹⁰ m, 4.69·10⁻¹⁰ m,3.94·10⁻¹⁰ m and 3.79·10⁻¹⁰ m.
 12. A mixture consisting of differentmodifications of compound 14 of formula

which comprises from 40 up to 100% by weight of β-crystalline formaccording to claim 11 .
 13. A process for the preparation of theβ-crystalline form of compound 14 according to claim 11 , whichcomprises crystallising, recrystallising or tempering compound 14 in thetemperature range from 95° C. to the melting point and then cooling itrapidly.
 14. A process for colour-stabilising amorphouspentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate),which comprises admixing a stabiliser from the class consisting of theorganic phosphites, phosphonites and/or benzofuran-2-ones to a meltconsisting ofpentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)and solidifying the mixture so obtained.
 15. Colour-stabilised amorphouspentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate)containing a sufficient stabilising amount of a stabiliser from theclass consisting of the organic phosphites, phosphonites and/orbenzofuran-2-ones.
 16. A stabiliser composition, which comprises a)pentaerythritol-tetrakis(3-[3′,5′-di-tert-butyl-4′-hydroxyphenyl]propionate),and b) a compound of the benzofuran-2-one type.
 17. A composition, whichcomprises A) an organic material susceptible to oxidative, thermalor/and actinic degradation or build-up, and B) the amorphous form of acompound according to claim 7 , the β-crystalline form of compound 14according to claim 11 and/or the stabiliser composition according toclaim 16 as stabiliser.
 18. A process for stabilising organic materialagainst oxidative, thermal or actinic degradation or build-up, whichcomprises adding to the material the amorphous form of a compoundaccording to claim 7 , the β-crystalline form of compound 14 accordingto claim 11 and/or the stabiliser composition according to claim 16 asstabiliser.
 19. A process according to claim 18 , wherein 0.01 to 15parts by weight of the stabiliser are added to 100 parts by weight oforganic material to be stabilised.
 20. A process according to claim 18 ,wherein the organic material is a synthetic thermoplastic polymer.
 21. Aprocess according to claim 18 , wherein a customary additive is added asfurther component.